The $2 bill that symbolized a second chance at love.

Robert Gschaar, 55, was working at Aon, an insurance brokerage, on the 92nd floor of the South Tower. That morning, after his wife, Myrta, heard the North Tower had been hit, she phoned him. He said he was safe and awaiting evacuation instructions, and he ended by saying "I love you and I'll call you." Those were the last words she heard from him.

In late 2003, Myrta received another phone call: The NYPD property clerk had some of her late husband's belongings. It took two years for her to gather the strength to collect them, and when she did, she picked up his wallet and wedding ring. But what made her break down was what she found tucked in the billfold. When Robert had proposed to Myrta in 1988, he had given her two $2 bills—a symbol that theirs was a second marriage and a second chance at love—and from that day on, each had carried one. His was still there in the wallet.

The leash that kept a patrol dog close to his family.

On September 11, Port Authority Police Lieutenant David W. Lim was on duty at the World Trade Center, along with his faithful partner, Sirius, a yellow Labrador retriever. They were bound by work and in life: Sirius, like other patrol dogs, lived with his handler, Lim, and Lim's family.

Lieutenant Lim was in the basement of the South Tower that morning when he felt the building shake violently. He thought a bomb had exploded, so he secured Sirius in his kennel and went to investigate but not before telling his canine partner, "I'll be back for you."

Lim ended up assisting evacuees from the North Tower and then got buried in rubble in the 5th floor stairwell. Miraculously, his section remained intact, sheltering him and 15 others until they could be rescued. Lim suffered a concussion, lower back contusions, and leg bruises; sadly, Sirius, whom Lim called "the best partner I ever had," did not survive. In February 2002, canine remains were found in the South Tower's kennel area. A ceremonial removal was held, complete with a full honor guard to commemorate Sirius' service, and, of course, Lim was there to salute him one last time.

The flight attendant's wings that brought comfort to others.

Sara Low, 28, was one of the flight attendants on American Airlines 11, and her AA wings were one of her proudest possessions. These wings were not the ones Sara was wearing that day, but were presented to the Low family shortly after 9/11 by Karyn Ramsey, a fellow flight attendant and Sara's former roommate. As Sara's father, Mike Low, said, the pin was "a touchstone to Sara, a really, really emotional thing for me personally." On November 1, 2001, Low asked a friend at the Pentagon whether the wings could be given to one of the U.S. troops in Afghanistan responding to the 9/11 attacks. Sergeant Mark Baker of the 160th Special Operations Aviation Regiment volunteered to wear them, bringing Sara's pin on some 20 missions he flew, often while under enemy attack. Before each mission, he and his crew mates made a ritual of rubbing the wings for good luck.

On May 21, 2002, Baker returned the wings to Mike Low, who decided to give them back to Karyn Ramsey. Still working for American Airlines, Karyn wore them for years before donating them to the National September 11 Memorial Museum in order to share the story of their journey.

The firefighter's reminder of the day.

At 8:50 am on September 11, a call came in to Engine 16 in Manhattan; a plane had crashed into one of the Towers. FDNY Lieutenant Mickey Kross and his colleagues reported to the North Tower and began evacuating people. He was on the third floor when he said, "It went dark, and then the next thing was just total silence. Nothing. No winds, no noise, no light." Soon after, he said, "I started hearing moaning....And I realized I wasn't alone."

Four hours later, Lieutenant Kross recalled, "The strangest thing happened. This beam of sunlight came right in on us." Rescuers had cleared away debris. Kross was able to climb a rope out of the stairwell. As he walked in a daze through the smoldering Towers, he found an intact playing card—a two of clubs—and kept it. Later, he penned a line on the card that came from William Shakespeare's Richard III: "Stand the hazard of the die," which he felt captured his experiences.

The Stories They Tell

All of these images and descriptions are from the new book, The Stories They Tell: Artifacts from the National September 11 Memorial Museum. On its cover is the helmet that was worn by FDNY's Mickey Kross that day. The museum will open spring 2014.